---
title: "Which blood tests are used for irregular periods?"
type: symptom
url: "https://www.test-well.com/symptoms/irregular-periods"
symptom: Irregular periods
aliases:
  - missed periods
  - irregular menstrual cycle blood test
  - amenorrhea tests
reviewed_at: 2026-09-06
review_status: reviewed
date_published: 2026-09-05
lab_fee_usd: 6
---

# Which blood tests are used for irregular periods?

> Irregular or missed periods are evaluated with the hormones that run the cycle — FSH, LH, estradiol and progesterone — plus prolactin, TSH and androgens (testosterone, DHEA-S), which cover the common disruptors: PCOS, thyroid disease, high prolactin and perimenopause. Timing the draw to your cycle matters and is noted below.


## When should you see a clinician instead of ordering a test?

- Very heavy bleeding (soaking a pad an hour for several hours), bleeding with dizziness or fainting — seek care
- Missed periods with a positive or possible pregnancy and pelvic pain — seek care promptly

## Why these tests for irregular periods?

The ratio of LH to FSH and the androgen levels point toward PCOS; a high FSH with low estradiol suggests diminished ovarian reserve or menopause transition; high prolactin and thyroid disease each disrupt ovulation and are easy to miss without testing. Pregnancy is always excluded first.

## Which conditions do these tests help evaluate?

- [PCOS](https://www.test-well.com/conditions/pcos) — Androgens, LH/FSH, insulin and thyroid markers to investigate PCOS.
- [Perimenopause](https://www.test-well.com/conditions/perimenopause) — Estradiol, FSH, LH and thyroid to make sense of changing cycles and symptoms.
- [Thyroid Problems](https://www.test-well.com/conditions/thyroid-problems) — TSH, Free T4/T3 and antibodies to evaluate an under- or over-active thyroid.

## Which tests, and what do they cost?

| Test or panel | Type | Price | All-in (one item + $6 fee) | Fasting | Results |
| --- | --- | --- | --- | --- | --- |
| [Women's Hormone Panel](https://www.test-well.com/tests/womens-hormone-panel) | Panel (11 tests) | $239.99 | $245.99 | No | 3–5 business days |
| [Women's Fertility Essentials](https://www.test-well.com/tests/female-fertility-panel) | Panel (5 tests) | $119.99 | $125.99 | No | 3–5 business days |
| [Menopause Assessment Panel](https://www.test-well.com/tests/menopause-panel) | Panel (8 tests) | $179.99 | $185.99 | No | 2–4 business days |
| [FSH (Follicle Stimulating Hormone)](https://www.test-well.com/tests/fsh) | Test | $29.99 | $35.99 | No | 2–4 business days |
| [LH (Luteinizing Hormone)](https://www.test-well.com/tests/luteinizing-hormone) | Test | $36.99 | $42.99 | No | 1–3 business days |
| [Estradiol (E2)](https://www.test-well.com/tests/estradiol) | Test | $35.99 | $41.99 | No | 1–3 business days |
| [Progesterone](https://www.test-well.com/tests/progesterone) | Test | $31.99 | $37.99 | No | 1–3 business days |
| [Prolactin](https://www.test-well.com/tests/prolactin) | Test | $39.99 | $45.99 | No | 2–4 business days |
| [TSH (Thyroid Stimulating Hormone)](https://www.test-well.com/tests/tsh) | Test | $26.99 | $32.99 | No | 1–3 business days |
| [Testosterone, Free & Total](https://www.test-well.com/tests/testosterone-free-and-total) | Test | $54.99 | $60.99 | No | 3–5 business days |
| [DHEA-Sulfate](https://www.test-well.com/tests/dhea-sulfate) | Test | $32.99 | $38.99 | No | 1–3 business days |

Prices are cash-pay; every order adds one $6.00 lab processing fee. Physician authorization included.

## Common questions

### What day of my cycle should I test?

FSH, LH and estradiol are usually drawn on cycle days 2–5; progesterone about 7 days after ovulation (day 21 of a 28-day cycle). If cycles are absent or very irregular, any day works and your clinician interprets accordingly.

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---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-06. Review policy: https://www.test-well.com/editorial-policy

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Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.